The slippery feel is likely the result of oil from your hands getting on the steering wheel - assuming you haven't used a cleaning solution that caused it. You can try cleaning the steering wheel, just make sure it will cut through the oils on there rather than making it worse. Something like the Autoglym Leather Cleaner should do the trick: amzn.to/2vMd6qW

Or Autoglym's Leather Balm, which should help soften the wheel and make it grippier: amzn.to/2W19EYt